JP6103227B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device in which a member made of a resin material is interposed between an electrode terminal and a case.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. The secondary battery has a case made of metal (for example, aluminum alloy or stainless steel) and an electrode terminal made of metal (aluminum alloy or copper alloy). The electrode terminal extends from the inside of the case to the outside in a state of being inserted through the through hole of the case. In such a secondary battery, an insulating member made of an electrically insulating resin material (for example, polypropylene [PP]) is attached to the through hole of the case in a state of being interposed between the case and the electrode terminal. (For example, refer to Patent Document 1). By this insulating member, the case and the electrode member are electrically insulated.

JP 2002-304973 A

  By the way, in the production of the secondary battery, after attaching the component parts such as the electrode terminal, the electrode terminal is attached to the case, such as welding the lid of the shape closing the opening to the case body. Some cases are welded. In such a secondary battery, the case becomes hot as the welding process is performed, so that the contact portion of the case with the insulating member also becomes hot. In this case, since the insulating member made of a resin material is vulnerable to heat, it may be deformed by the heat, which is not preferable because it causes a decrease in the function of the insulating member.

  It is not limited to the insulating member described above, and any synthetic resin member interposed between the case and the electrode terminal, such as a synthetic rubber O-ring for sealing between the case and the electrode terminal. The thermal deformation accompanying welding of the case can occur in the same way.

  In the technique disclosed in Patent Document 1, a thin portion for increasing the heat conduction resistance is formed between the peripheral edge of the lid welded by laser and the insulating member of the electrode terminal. Propose that. However, as described in Patent Document 1, it is necessary to set the thickness of the thin portion to a thickness that does not cleave against a rise in pressure inside the battery. For this reason, when the thickness of the battery can (case) or the lid is set to be thin in advance in order to reduce the weight, it is difficult to adopt.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is because the interposed member provided between the case and the electrode terminal originates in the welding process of the same case. An object of the present invention is to provide a power storage device that can suppress thermal deformation.

Hereinafter, a power storage device for achieving the above object includes a metal case having a welded portion and a through hole to be welded, and a metal that is inserted through the through hole and extends from the inside of the case to the outside An electrical storage device having an electrode terminal made of synthetic resin and an interposition member made of synthetic resin interposed between the case and the electrode terminal, wherein the case includes a case body having an opening and the opening. consists of a lid for closing the lid body has the through hole, the weld is a portion joined by welding and the case body and the lid, of the case, the lid only low thermal conductive layer compared to its forming material made of a low forming material having a thermal conductivity, and summarized in that provided integrally in a manner which constitutes a contact surface with the interposition member.

  According to the above power storage device, the case covered with the low thermal conductive layer is in contact with the interposed member even though the case becomes hot as the welded portion is welded. The amount of heat conducted from the case to the interposed member can be reduced as compared with the power storage device that is not provided. Thereby, since the temperature rise of an interposed member can be suppressed, it can suppress that an interposed member heat-deforms resulting from the welding process of a case.

  According to the power storage device, when the lid is joined to the case body by welding, thermal deformation of the interposed member interposed between the electrode terminal inserted into the through hole of the lid and the lid Can be suppressed.

In the above power storage device, the interposed member is preferably an insulating member that electrically insulates between the lid and the electrode terminal.
According to the power storage device, thermal deformation of the insulating member provided between the lid and the electrode terminal can be suppressed during the case welding process. Therefore, it is possible to suppress a decrease in the insulating function due to the deformation of the insulating member.

In the above power storage device, the electrode terminal has a pole portion provided with a flange portion having a cross-sectional area larger than an opening area of the through hole at one end, and the flange portion is disposed in the case. And the pole column portion is inserted through the through-hole, and the tip of the pole column portion protrudes out of the case. The power storage device includes the pole column A metal fastening member fastened and fixed to the part from the outside of the case, wherein the insulating member is between the flange part and the inner surface of the lid , and the outer surface of the pole column part and the penetration It may be interposed between the inner surface of the hole and between the outer surface of the lid and the fastening member.

In the above power storage device, the insulating member is interposed between the inner surface of the through hole and the outer surface of the pole column portion by fastening the fastening member to the pole column portion of the electrode terminal, and the insulating member is fastened. between the outer surface of the member and the lid member, and each narrow pressure state between the flange portion of the inner surface and the electrode terminals of the lid body, the electrode terminal is fastened and fixed to the case. According to the power storage device, such thermal deformation of the insulating member can be suppressed.

In the above power storage device, the interposed member is preferably a seal member that seals between the lid and the electrode terminal.
According to the power storage device, thermal deformation of the seal member provided between the lid and the electrode terminal can be suppressed during the case welding process. Therefore, it is possible to suppress a decrease in the sealing function due to unnecessary deformation of the sealing member.

In the above power storage device, it is preferable that the case is made of an aluminum alloy, and the low thermal conductive layer is made of alumina.
According to the power storage device, the low thermal conductive layer made of alumina having low thermal conductivity can be formed on the surface of the case made of aluminum alloy by a processing method such as a position method (PJD method) using powder jet. The amount of heat conduction from the case to the interposed member can be suppressed by the low heat conductive layer.

  The power storage device can be applied to a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the interposed member provided between the case and the electrode terminal is thermally deformed due to the welding process of the case.

The disassembled perspective view which shows the secondary battery of one Embodiment. The perspective view which shows the external appearance of a secondary battery. Sectional drawing which shows the pole column part periphery of an electrode terminal. The top view of the cover body of a case. Sectional drawing of the cover body in alignment with line 5-5 in FIG. The bottom view of a cover body.

Hereinafter, an embodiment in which the power storage device is embodied as a secondary battery will be described.
As shown in FIG. 1 or FIG. 2, in the secondary battery 10, an electrode assembly 20 is accommodated in the case 12. The case 12 includes a rectangular parallelepiped case main body 13 having an opening 13 d and a rectangular flat plate-shaped lid body 14 that closes the opening 13 d of the case main body 13. The case body 13 and the lid body 14 are both made of metal (aluminum alloy), and the joint portion (welded portion 15 in FIG. 2) between the case body 13 and the lid body 14 is joined by a welding process such as laser welding. Yes. The case body 13 includes a rectangular bottom plate 13a, a short side wall 13b erected from a pair of opposed short side edges of the bottom plate 13a, and a long side wall 13c erected from a pair of long side edges of the bottom plate 13a. With. The lid body 14 has a pair of through holes 14b arranged in parallel at a predetermined interval. Further, the secondary battery 10 of the present embodiment is a prismatic battery whose outer periphery forms a square shape. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  As shown in FIG. 1, the electrode assembly 20 includes a positive electrode 21 and a negative electrode 22, and a laminate that forms a layer by interposing a separator that insulates between the positive electrode 21 and the negative electrode 22. Has been. In the electrode assembly 20, the positive electrode tab 31 connected to the positive electrode 21 is welded to the positive electrode conductive member 33, and the negative electrode tab 32 connected to the negative electrode 22 is welded to the negative electrode conductive member 37.

  Moreover, as shown in FIG. 1 or FIG. 3, the positive electrode conductive member 33 and the negative electrode conductive member 37 have a terminal connection portion 34 having a square plate shape. In the terminal connecting portion 34, a surface to which a positive electrode terminal 41 or a negative electrode terminal 42 as an electrode terminal described later is welded is a first surface 34a, and a surface opposite to the first surface 34a is a second surface 34b. The positive electrode conductive member 33 and the negative electrode conductive member 37 have a rising portion 35 that rises from the second surface 34 b toward the first surface 34 a, and tab welding that extends from the rising portion 35 in a direction away from the terminal connection portion 34. A portion 36 is provided. The tab weld 36 is a rectangular plate.

  The positive electrode terminal 41 is welded to the terminal connection portion 34 of the positive electrode conductive member 33, and the negative electrode terminal 42 is welded to the terminal connection portion 34 of the negative electrode conductive member 37. The positive electrode terminal 41 and the negative electrode terminal 42 each have a flange portion 43 having an octagonal plate shape, and the planar shape of the flange portion 43 is substantially the same as the planar shape of the first surface 34 a in each terminal connection portion 34. In the flange portion 43, the surface facing the inner surface 14a of the lid body 14 is a seat surface 43a, and the surface opposite to the seat surface 43a in the thickness direction of the flange portion 43 is an assembly side end surface 43b.

  A cylindrical pole post 44 is erected from the center of the flange 43, and a seating surface 43 a surrounds the pole post 44. The pole portion 44 has a male screw 44a on the outer peripheral surface and a female screw 44b as a screw groove on the inner peripheral surface. The male screw 44a and the female screw 44b are reverse screws.

  A terminal cover 50 made of synthetic resin (polyphenylene sulfide [PPS]) is attached to the collar portion 43. The terminal cover 50 includes a lid-side insulating plate 51 that is disposed between the seating surface 43 a of the flange portion 43 and the inner surface 14 a of the lid body 14. The lid-side insulating plate 51 has an insertion portion 51a into which the pole column portion 44 is inserted, and the inner peripheral edge of the lid-side insulating plate 51 is arcuate. The lid-side insulating plate 51 has a cut-out communication portion 51b that opens the insertion portion 51a to one side of the lid-side insulation plate 51. The lid-side insulation plate 51 is flat by the insertion portion 51a and the communication portion 51b. It has a U-shape. The lid-side insulating plate 51 has, on its inner edge, a protrusion 51c that faces the communication part 51b and protrudes toward the communication part 51b.

  The lid-side insulating plate 51 includes a case-side insulating plate 52 at an edge located on the opposite side of the communication portion 51b with the insertion portion 51a interposed therebetween, and the case-side insulating plate 52 extends from the lid body 14. It extends in the direction of leaving. The case side insulating plate 52 has a rectangular plate shape and extends perpendicularly to the lid side insulating plate 51. In the case-side insulating plate 52, an assembly-side insulating plate 53 extends in the same direction as the lid-side insulating plate 51 and extends along the assembly-side end surface 43 b at the tip of the case-side insulating plate 52. . The case side insulating plate 52 is formed in a rectangular plate shape. The terminal cover 50 configured as described above is attached to the positive terminal 41 and the negative terminal 42 from the side of the short side wall 13b of the case body 13.

The pole column portion 44 is inserted into the insertion portion 51 a of the lid side insulating plate 51, and the lid side insulating plate 51 surrounds almost the entire circumference of the pole column portion 44. The lid-side insulating plate 51 is supported on the seating surface 43 a of the flange portion 43. On the seating surface 43 a of the flange portion 43, a synthetic rubber O-ring 56 as a sealing member is provided so as to surround the entire circumference of the pole column portion 44. The O-ring 56 is disposed in the insertion portion 51 a of the lid-side insulating plate 51, and substantially entirely surrounded by the lid-side insulating plate 51. That, O-ring 56, other than the region facing the communicating portion 51b is surrounded by the inner peripheral edge of the cover-side insulating plate 51. The assembly-side insulating plate 53 is disposed closer to the electrode assembly 20 than the assembly-side end surface 43b of the flange 43, and extends along the assembly-side end surface 43b opposite to the seating surface 43a. The assembly-side insulating plate 53 is interposed between the flange 43 and the electrode assembly 20.

  The lid 14, the positive terminal 41, and the negative terminal 42 are electrically insulated by the lid-side insulating plate 51 in the terminal cover 50. In addition, the case body insulating plate 52 electrically insulates the case body 13 from the positive terminal 41 and the negative terminal 42. Further, the assembly side insulating plate 53 electrically insulates the electrode assembly 20 from the positive terminal 41 and the negative terminal 42.

  The tip of the pole post 44 inserted into the insertion part 51a of the lid-side insulating plate 51 protrudes outside the case 12 from a through hole 14b provided in the lid 14 so as to communicate the inside of the case 12 with the outside. (Exposed). The flange portions 43 of the positive electrode terminal 41 and the negative electrode terminal 42 are provided at one end located inside the case main body 13 among both ends of the pole column portion 44. Moreover, the collar part 43 is set so that the cross-sectional area parallel to the cover body 14 is larger than the opening area of the through-hole 14b. For this reason, the collar part 43 cannot be pulled out from the through hole 14 b inside the case main body 13. The inner peripheral surface of the through hole 14b of the lid body 14 and the outer peripheral surface of the pole post 44 are insulated by an insulating member 19 made of synthetic resin (PPS).

  The insulating member 19 includes a cylindrical tubular portion 24 and an annular flange portion 25 that extends radially outward from one axial end of the tubular portion 24. In this insulating member 19, the cylindrical portion 24 is in a state of extending between the inner peripheral surface of the through hole 14 b and the outer peripheral surface of the pole column portion 44, and the flange portion 25 is formed on the outer surface 14 c of the lid body 14 of the case 12. The lid 14 is provided so as to extend along the line. A nut 55 as a fastening member is screwed to the male screw 44 a of the pole column portion 44, and the nut 55 is attached (fastened and fixed) to the pole column portion 44.

  In the secondary battery 10, the cylindrical portion 24 interposed between the inner peripheral surface of the through hole 14 b of the lid body 14 and the outer peripheral surface of the pole column portion 44, and the nut 55 and the lid body 14 are sandwiched. The nut 55 and the lid body 14 are insulated from each other by the pressed flange portion 25. Further, the nut 55 is screwed into the male screw 44 a of the pole column portion 44, whereby the flange portion 25, the lid body 14, the lid-side insulating plate 51, and the O between the nut 55 and the flange portion 43 of the pole column portion 44. The pole post 44 is fastened and fixed to the lid 14 with the ring 56 being tightly pressed. The O-ring 56 in the fastened state is in close contact with the inner surface 14a of the lid body 14 and the seating surface 43a of the flange portion 43 in a compressed state, and seals the periphery of the through hole 14b.

  In the secondary battery 10, various components such as the electrode terminals (the positive electrode terminal 41 and the negative electrode terminal 42) and the electrode assembly 20 are attached to the lid body 14, and then the joint portion (weld) between the case main body 13 and the lid body 14. The part 15) is joined and fixed by welding.

  In the secondary battery 10 of the present embodiment, the lid 14 of the case 12 is configured to form a contact surface with the insulating member 19, a contact surface with the terminal cover 50, and a contact surface with the O-ring 56. The low thermal conductive layer 60 made of a forming material (aluminum oxide [alumina]) having a lower thermal conductivity than the forming material (aluminum alloy) of the case 12 is integrally provided.

  In the present embodiment, the low thermal conductive layer 60 is formed on the surface of the lid body 14 using a powder jet deposition method (PJD method). In this PJD method, the low thermal conductive layer 60 made of alumina is formed by spraying and depositing (lamination) alumina fine particles on the surface of the lid 14 at a high speed.

Hereinafter, the low thermal conductive layer 60 will be described in detail.
As shown in FIGS. 4 and 5, the contact surface that contacts the flange portion 25 of the insulating member 19 on the outer surface 14c of the lid body 14 has a low thermal conductive layer 60a made of alumina. The low heat conductive layer 60a has a shape that covers the entire portion of the lid body 14 that contacts the flange portion 25. Specifically, the entire periphery of the through hole 14b including the open end of the through hole 14b in the lid body 14 is formed. An annular shape extending around the circumference. In FIG. 5, the thickness of the low thermal conductive layer 60 is exaggerated for easy understanding.

  Further, the inner peripheral surface of the through-hole 14b of the lid body 14, that is, the contact surface that comes into contact with the tubular portion 24 of the insulating member 19 has a low thermal conductive layer 60b made of alumina. The low thermal conductive layer 60b has a shape that covers the entire portion of the lid body 14 that contacts the cylindrical portion 24, and more specifically, has a cylindrical shape that covers the entire inner surface of the through hole 14b in the lid body 14.

  As shown in FIGS. 5 and 6, the contact surface of the inner surface 14a of the lid 14 that contacts the lid-side insulating plate 51 and the O-ring 56 of the terminal cover 50 has a low thermal conductive layer 60c made of alumina. The low heat conductive layer 60c has a shape that covers the entire portion of the lid 14 that contacts the lid-side insulating plate 51 and the entire portion of the lid 14 that contacts the O-ring 56, and more specifically, the through hole 14b in the lid 14. It is an annular shape extending over the entire circumference of the through-hole 14b including the open end. An inner portion of the low heat conductive layer 60c adjacent to the through hole 14b is in contact with the O-ring 56, and an outer portion on the side away from the through hole 14b is in contact with the lid-side insulating plate 51.

Next, the operation of the low thermal conductive layer 60 will be described.
In the secondary battery 10, the contact surface with the flange portion 25 of the insulating member 19 in the lid body 14 of the case 12 has a low heat conductive layer 60 a, and the cylindrical portion 24 of the insulating member 19 in the lid body 14 The contact surface has a low thermal conductive layer 60b. Thus, when the secondary battery 10 is manufactured, the cover 14 of the case 12 is covered with the low thermal conductive layers 60a and 60b, although the case 12 becomes hot as the welded portion 15 of the case 12 is welded. The contact portion is in contact with the insulating member 19. Therefore, the amount of heat conducted from the case 12 to the insulating member 19 can be reduced as compared with a secondary battery that does not have such a low thermal conductive layer.

  Further, in the secondary battery 10, the contact surface with the terminal cover 50 and the contact surface with the O-ring 56 in the lid 14 of the case 12 have the low thermal conductive layer 60 c. As a result, the cover 14 of the case 12 is in contact with the terminal cover 50 and the O-ring 56 at the portion covered with the low thermal conductive layer 60 c. Therefore, when the secondary battery 10 is manufactured, the amount of heat conducted from the case 12 to the terminal cover 50 and the O-ring 56 is reduced even though the case 12 becomes hot as the welded portion 15 of the case 12 is welded. can do.

According to the above embodiment, the following effects can be obtained.
(1) The contact surface with the flange portion 25 of the insulating member 19 in the lid body 14 of the case 12 has the low heat conductive layer 60a, and the contact surface with the tubular portion 24 of the insulating member 19 in the lid body 14. Has a low thermal conductive layer 60b, and the contact surface of the lid 14 with the terminal cover 50 has a low thermal conductive layer 60c. Thereby, since the amount of heat conducted from the case 12 to the insulating member 19 and the terminal cover 50 can be reduced, an increase in temperature of the insulating member 19 and the terminal cover 50 can be suppressed. Therefore, the thermal deformation of the insulating member 19 and the terminal cover 50 due to the welding of the case 12 can be suppressed, and the insulation function and the fastening force of the nut 55 are reduced due to the deformation of the insulating member 19 and the terminal cover 50. Can be suppressed.

  (2) The contact surface of the lid 14 of the case 12 with the O-ring 56 has a low thermal conductive layer 60c. As a result, the amount of heat conducted from the case 12 to the O-ring 56 can be reduced, so that the temperature rise of the O-ring 56 can be suppressed. Therefore, thermal deformation of the O-ring 56 due to the welding process of the case 12 can be suppressed, and deterioration of the sealing function due to unnecessary deformation of the O-ring 56 can be suppressed.

  (3) A low thermal conductive layer 60 made of alumina having a low thermal conductivity is formed on the surface of the case 12 made of an aluminum alloy. Therefore, the amount of heat conducted from the case 12 to the insulating member 19, the terminal cover 50, and the O-ring 56 interposed between the case 12 and the electrode terminal can be suppressed by the low thermal conductive layer 60.

  (4) The low thermal conductive layer 60 is formed on the material made of the aluminum alloy of the lid body 14 by the PJD method. Therefore, the shape of the material made of the aluminum alloy of the lid body 14 does not require large unevenness such as a thin-walled portion, and the adoption of the present invention does not cause a decrease in the strength and rigidity of the lid body 14. For this reason, application is easy even when the case 12 and the lid 14 are thinned.

The above embodiment may be modified as follows.
If the proper insulating function is obtained, the insulating member 19 and the terminal cover 50 may be formed of a synthetic resin material (for example, PP) other than PPS.

  ○ The processing method used for forming the low thermal conductive layer 60 is not limited to the PDJ method, and any processing method capable of forming an alumina layer on the surface of an aluminum alloy, such as a vapor deposition method, a thermal spraying method, an oxide film method, Any processing method can be adopted.

As long as the shape of the low thermal conductive layer 60a includes the contact surface with the flange portion 25 of the insulating member 19, the shape of the outer edge can be any shape such as a polygonal shape.
○ If the shape of the low heat conductive layer 60c includes a contact surface with the terminal cover 50 and a contact surface with the O-ring 56, the outer portion (portion where the terminal cover 50 contacts) extends in a substantially C shape. Or it can be made into arbitrary shapes, such as the shape where an outer edge becomes a polygonal shape.

  One of the low thermal conductive layer 60a, the low thermal conductive layer 60b, the inner part of the low thermal conductive layer 60c (the part where the O-ring 56 contacts), and the outer part of the low thermal conductive layer 60c (the part where the terminal cover 50 contacts). Can be omitted, any two can be omitted, or any three can be omitted. If the thermal deformation of the insulating member 19 at the time of welding is appropriately suppressed, the low heat conductive layer 60a and the low heat conductive layer 60b can be omitted. Further, if it is possible to appropriately suppress the thermal deformation of the O-ring 56 during welding, the inner portion of the low heat conductive layer 60c may be omitted. Furthermore, if the thermal deformation of the terminal cover 50 during welding is appropriately suppressed, the outer portion of the low thermal conductive layer 60c can be omitted.

  The configuration in which the low thermal conductive layer 60 is formed on the contact surface in the case 12 is not limited to the secondary battery 10 having the welded portion 15 where the case body 13 and the lid body 14 are joined by welding, such as a pressure regulating valve. The present invention can also be applied to a secondary battery having a welded portion where another member is welded to the case.

  ○ The metal material forming the case 12 and the material forming the low thermal conductive layer 60 are arbitrarily changed as long as the thermal conductivity of the low thermal conductive layer 60 forming material is lower than that of the case 12 forming material. be able to. For example, the case 12 can be formed of an iron-based material such as stainless steel, and the low thermal conductive layer 60 can be formed of a ceramic material other than alumina such as zirconia or a metal material other than stainless steel.

  The low thermal conductive layer 60 of the above embodiment is not limited to the secondary battery 10 in which the nut 55 is screwed to the pole column portion 44 in order to fasten and fix the electrode terminal to the case 12, but is caulked to the pole column portion of the electrode terminal. The present invention can also be applied to a secondary battery in which members are caulked and fixed.

  Not only the O-ring 56 made of synthetic rubber but also a seal member of any material and shape as long as it is a seal member that can seal between the electrode terminal and the lid body 14 around the entire circumference of the pole column portion 44. A member can be provided.

The case 12 may be formed in a columnar shape or an elliptical columnar shape.
The power storage device may be embodied as a nickel hydride secondary battery or an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12 ... Case, 13 ... Case main body, 13d ... Opening part, 14 ... Cover body, 14a ... Inner surface, 14b ... Through-hole, 14c ... Outer surface, 15 ... Welding part, 19 ... Via Insulating member as an installation member, 24 ... cylindrical part, 25 ... flange part, 41 ... positive electrode terminal as electrode terminal, 42 ... negative electrode terminal as electrode terminal, 43 ... collar part, 44 ... pole column part, 50 ... via Terminal cover as installation member, 51... Lid side insulating plate, 55... Nut as fastening member, 56... O-ring as interposition member and seal member, 60, 60a, 60b, 60c.

Claims (6)

A metal case having a welded portion and a through-hole to be welded, a metal electrode terminal inserted through the through-hole and extending from the inside of the case to the outside, the case and the electrode terminal, A power storage device having a synthetic resin interposed member interposed therebetween,
The case is composed of a case main body having an opening and a lid for closing the opening.
The lid has the through hole,
The welded part is a part that joins the case body and the lid by welding,
Of the case , only the lid is integrally provided with a low heat conductive layer made of a forming material having a low thermal conductivity compared to the forming material so as to form a contact surface with the interposed member. A power storage device. The power storage device according to claim 1, wherein the interposed member is an insulating member that electrically insulates between the lid and the electrode terminal. The electrode terminal has a pole portion provided with a flange portion having a cross-sectional area larger than the opening area of the through hole at one end, the flange portion is disposed in the case, and the through-hole The pole column is inserted into the hole, and the tip of the pole column is provided in the case in a state protruding from the case;
The power storage device includes a metal fastening member that is fastened and fixed to the pole column portion from the outside of the case,
The insulating member is between the flange and the inner surface of the lid , between the outer surface of the pole column and the inner surface of the through hole, and between the outer surface of the lid and the fastening member. The power storage device according to claim 2 , wherein the power storage device is interposed in the battery. The power storage device according to claim 1, wherein the interposition member is a seal member that seals between the lid and the electrode terminal. The case is made of an aluminum alloy,
The low thermal conductive layer, the electric storage device according to any one of claims 1 to 4 consisting of alumina. The power storage device according to any one of claims 1 to 5 , wherein the power storage device is a secondary battery.